Detached Garage & 3way

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Smart $ said:
From a pure technical standpoint, I don't believe 225.30(D) even matters for this. As you say, headings matter, and 225.30 is "Number of Supplies". A 3-way switch-loop from additional building to the originating building and back is not a "supply". It would have to power a load at the originating building for it to be a "supply" there, which it does not, and it does not constitute a second "supply" when it returns to the additional building for that is where the "building supply" originated. :roll:;):D
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You should be a politician. :grin:
 
Smart $ said:
From a pure technical standpoint, I don't believe 225.30(D) even matters for this. As you say, headings matter, and 225.30 is "Number of Supplies". A 3-way switch-loop from additional building to the originating building and back is not a "supply". It would have to power a load at the originating building for it to be a "supply" there, which it does not, and it does not constitute a second "supply" when it returns to the additional building for that is where the "building supply" originated. :roll:;):D
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Consider a not-uncommon arrangement at a dwelling with a detatched garage. An outside light at the dwelling back door and an outside light at the garage entry, both controlled, together, by a single set of two 3-way switches.

Your turn of phrase seems to say this is prohibited, no?

While the 3-way switching is "supplied" for the utilization equipment attached at the lighting outlets, this supply is not a building wiring system supply, and, IMO is specifically allowed in 225.30(D).
 
al hildenbrand said:
Consider a not-uncommon arrangement at a dwelling with a detatched garage. An outside light at the dwelling back door and an outside light at the garage entry, both controlled, together, by a single set of two 3-way switches.

Your turn of phrase seems to say this is prohibited, no?

While the 3-way switching is "supplied" for the utilization equipment attached at the lighting outlets, this supply is not a building wiring system supply, and, IMO is specifically allowed in 225.30(D).
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No, I'm not saying it would be prohibited at all. I was just saying where there was only a load at the garage and powered by the garage's supply, it didn't have to qualify under 225.30(D). The scenario you present would because there are loads at both buildings.
 
Dennis Alwon said:
I still am not sure why the wording was changed in 225.30.
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Have you seen the IAEI analysis? According to them, "The previous text would permit an unlimited number of feeders or branch circuits to be established back to the original building."
 
Back to the original question about the 3-way conductors being in the feeder raceway and box. If this is a feeder with a separate EGC, I think the approach is fine. If this is an older building with a grounded neutral being the EGC, then you'd have to watch out for 250.32 and not create a parallel grounded path between buildings.

If you can prevent the EGC in the 3-way from being spliced in the panel, then you're probably OK as long as the switch boxes don't share any conductors with other circuits from their same building (which would require tying grounds together).
 
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